Flow balanced heat exchanger for battery thermal management

Abstract

A heat exchanger for cooling batteries in hybrid or electric vehicles includes a plurality of spaced apart, discrete heat exchanger panels, each having a coolant inlet manifold section, a coolant outlet manifold section, and a plurality of coolant flow passages extending between the inlet and outlet manifold sections. The inlet and outlet manifold sections of the discrete panels are connected by tubes to define continuous coolant inlet and outlet manifolds, each having a coolant opening. The flow of coolant through discrete panels may be balanced by providing the fluid flow passages of the panels with various cross-sectional areas and/or hydraulic diameters, depending partly on the proximity of each panel to the coolant opening. In an embodiment, where the panels are formed from pairs of stamped plates, variation of the cross-sectional area and/or hydraulic diameter of the coolant flow passages may be achieved by deliberately offsetting the plates during assembly.

What is claimed is: 
     
       1. A heat exchanger, comprising:
 (a) a plurality of discrete heat exchanger panels, each of the heat exchanger panels having an inlet manifold section, an outlet manifold section, and a plurality of fluid flow passages extending between the inlet and outlet manifolds; 
 (b) at least one inlet manifold tube, wherein each said inlet manifold tube connects the inlet manifold sections of an adjacent pair of said discrete heat exchanger panels, wherein an inlet manifold of the heat exchanger comprises the inlet manifold sections of the discrete heat exchanger panels and the at least one inlet manifold tube; 
 (c) at least one outlet manifold tube, wherein each said outlet manifold tube connects the outlet manifold sections of an adjacent pair of said discrete heat exchanger panels, wherein an outlet manifold of the heat exchanger comprises the outlet manifold sections of the discrete heat exchanger panels and the at least one outlet manifold tube; 
 (d) an inlet opening provided in said inlet manifold; and 
 (e) an outlet opening provided in said outlet manifold; 
 wherein the heat exchanger has a longitudinal axis, and wherein the inlet manifold and the outlet manifold are parallel to the longitudinal axis; 
 wherein each of the discrete heat exchanger panels comprises a pair of stamped plates, each having a plurality of open channels, wherein the plates are joined together face-to-face to define said inlet manifold section, said outlet manifold section, and said plurality of fluid flow passages; 
 wherein the plurality of discrete heat exchanger panels includes a first heat exchanger panel and a second heat exchanger panel; 
 wherein each of the stamped plates has a pair of opposed, axially-extending edge portions in which open channels are defined for said inlet and outlet manifold sections, a central portion in which open channels are defined for said fluid flow passages, and a pair of opposed, transversely-extending edge portions; 
 wherein at least one of the transversely-extending edge portions and/or at least one of the axially extending edge portions of each of the stamped plates is provided with one or more indexing features which provide different degrees of axial alignment of the stamped plates in the first heat exchanger panel relative to the second heat exchanger panel; and 
 wherein said different degrees of axial alignment provide the fluid flow passages of the second heat exchanger section with a greater cross-sectional area or hydraulic diameter than the fluid flow passages of the first heat exchanger section. 
 
     
     
       2. The heat exchanger according to  claim 1 , wherein the stamped plates are identical. 
     
     
       3. The heat exchanger according to  claim 1 , wherein the inlet and outlet manifold sections of the discrete heat exchanger panels are parallel to one another and each have a pair of open ends. 
     
     
       4. The heat exchanger according to  claim 3 , wherein the fluid flow passages are substantially perpendicular to the inlet and outlet manifold sections. 
     
     
       5. The heat exchanger according to  claim 1 , wherein the discrete heat exchanger panels each have a pair of flat, opposed faces which are traversed by said fluid flow passages. 
     
     
       6. The heat exchanger according to  claim 1 , wherein the transversely-extending edge portions of adjacent pairs of said discrete heat exchanger panels are axially spaced apart. 
     
     
       7. The heat exchanger according to  claim 1 , wherein the inlet and outlet openings are provided at the same end of the heat exchanger. 
     
     
       8. The heat exchanger according to  claim 1 , wherein the inlet and outlet openings are provided at opposite ends of the heat exchanger. 
     
     
       9. The heat exchanger according to  claim 1 , wherein the indexing features are provided in each of the stamped plates and comprise at least a first set of indexing holes and a second set of indexing holes provided in the transversely-extending edge portions of the stamped plates; and
 wherein alignment of the first set of said indexing holes in the first stamped plate with the first set of said indexing holes in the second stamped plate results in substantially complete axial alignment of the plates, such that there is substantially no offset of the open channels for the fluid flow passages in the first stamped plate relative to the open channels for the fluid flow passages in the second stamped plate; 
 alignment of the second set of said indexing holes in the first stamped plate with the second set of said indexing holes in the second stamped plate results in axial misalignment of the plates, such that there is a partial offset of the open channels for the fluid flow passages in the first stamped plate relative to the open channels for the fluid flow passages in the second stamped plate. 
 
     
     
       10. The heat exchanger according to  claim 9 , wherein the first and second stamped plates include a third set of said indexing holes, wherein:
 alignment of the third set of said indexing holes in the first stamped plate with the third set of said indexing holes in the second stamped plate results in axial misalignment of the plates, such that there is a partial offset of the open channels for the fluid flow passages in the first stamped plate relative to the open channels for the fluid flow passages in the second stamped plate; and 
 wherein the partial offset produced by alignment of the third sets of indexing holes produces a partial offset which is different from the partial offset produced by alignment of the second sets of indexing holes. 
 
     
     
       11. The heat exchanger according to  claim 9 , wherein each said set of indexing holes includes at least one indexing hole in each of the transversely-extending edge portions of each of the stamped plates. 
     
     
       12. The heat exchanger according to  claim 1 , wherein the first and second stamped plates each have an axial axis of symmetry. 
     
     
       13. A heat exchanger, comprising:
 (a) a plurality of discrete heat exchanger panels, each of the heat exchanger panels having an inlet manifold section, an outlet manifold section, and a plurality of fluid flow passages extending between the inlet and outlet manifolds; 
 (b) at least one inlet manifold tube, wherein each said inlet manifold tube connects the inlet manifold sections of an adjacent pair of said discrete heat exchanger panels, wherein an inlet manifold of the heat exchanger comprises the inlet manifold sections of the discrete heat exchanger panels and the at least one inlet manifold tube; 
 (c) at least one outlet manifold tube, wherein each said outlet manifold tube connects the outlet manifold sections of an adjacent pair of said discrete heat exchanger panels, wherein an outlet manifold of the heat exchanger comprises the outlet manifold sections of the discrete heat exchanger panels and the at least one outlet manifold tube; 
 (d) an inlet opening provided in said inlet manifold; and 
 (e) an outlet opening provided in said outlet manifold; 
 wherein the heat exchanger has a longitudinal axis, and wherein the inlet manifold and the outlet manifold are parallel to the longitudinal axis; 
 wherein each of the discrete heat exchanger panels comprises a pair of stamped plates, each having a plurality of open channels, wherein the plates are joined together face-to-face to define said inlet manifold section, said outlet manifold section, and said plurality of fluid flow passages; 
 wherein the plurality of discrete heat exchanger panels includes a first heat exchanger panel and a second heat exchanger panel; 
 wherein each of the stamped plates has a pair of opposed, axially-extending edge portions in which open channels are defined for said inlet and outlet manifold sections, a central portion in which open channels are defined for said fluid flow passages, and a pair of opposed, transversely-extending edge portions; 
 wherein the inlet and outlet manifold sections each have open ends, and wherein each of the open ends is cylindrical and is sized to receive one end of one of the tubes, wherein a sealed connection is provided between said open end and said one end of said tube; 
 wherein the at least one inlet manifold tube and the at least one outlet manifold tube are cylindrical; and 
 wherein the at least one inlet manifold tube and the at least one outlet manifold tube each have a wall thickness which is greater than a thickness of material from which the panels are formed. 
 
     
     
       14. The heat exchanger according to  claim 13 , wherein the at least one inlet manifold tube and the at least one outlet manifold tube are bendable. 
     
     
       15. The heat exchanger according to  claim 13 , wherein the sealed connection is a brazed connection. 
     
     
       16. The heat exchanger according to  claim 13 , wherein one or more flow restrictions are provided in at least the first heat exchanger panel, said one or more flow restrictions producing a reduced cross-sectional area and/or hydraulic diameter in the first heat exchanger panel. 
     
     
       17. The heat exchanger according to  claim 16 , wherein said one or more flow restrictions of the first heat exchanger panel are provided in at least some of the fluid flow passages, the inlet manifold section, and/or the outlet manifold section. 
     
     
       18. The heat exchanger according to  claim 17 , wherein each said flow restriction is in the form of a depression. 
     
     
       19. The heat exchanger according to  claim 18 , wherein each said depression is in the form of a crimp, a dimple, or a rib. 
     
     
       20. The heat exchanger according to  claim 18 , wherein the number and/or size of the depressions is varied in different fluid flow passages of the first heat exchanger panel, so as to provide different flow restrictions in two or more of the fluid flow passages of the first heat exchanger panel. 
     
     
       21. The heat exchanger according to  claim 16 , wherein said one or more flow restrictions of the first heat exchanger panel are provided in the at least one inlet manifold tube and/or the at least one outlet manifold tube. 
     
     
       22. The heat exchanger according to  claim 16 , wherein the second heat exchanger panel is adjacent to the first heat exchanger panel, wherein the first heat exchanger panel is proximal to at least one of the inlet opening and the outlet opening, and the second heat exchanger is distal to at least one of the inlet opening and the outlet opening. 
     
     
       23. The heat exchanger according to  claim 22 , wherein the second heat exchanger panel is free of said flow restrictions. 
     
     
       24. The heat exchanger according to  claim 22 , wherein the second heat exchanger panel is provided with one or more flow restrictions, and wherein the cross-sectional area and/or the hydraulic diameter in the second heat exchanger panel is greater than that in the first heat exchanger panel.